You can open chests for a split second while inside the nether portal

While I was playing in my survival world, I was in the middle of going through the nether portal and the portal animation was playing. But then, I remembered that I forgot something in the chest next to my portal, so I right clicked the chest and the chest opened for a split second before closing again. After this happened for the first time, I tried replicating what had happened and the same thing happened again.